I don't know much of anyhting concerning this stuff, but ran across an add for it in the new products page in Music Inc magazine. It looked pretty rad especially with the analog potentiometer inputs. Searched for it on this board, but didn't find anything. Maybe a good chip for a project? Here's the datasheet!
http://www.spinsemi.com/get_datasheet.php?prodnum=SPN1001&pdf=FV-1.pdf
very interesting, THANX a LOT! (http://get_datasheet.php?prodnum=SPN1001-DEV&pdf=SPINAsmUserManual.pdf)
:icon_cool:
Quote from: puretube on October 24, 2006, 01:26:10 PM
very interesting, THANX a LOT! (http://get_datasheet.php?prodnum=SPN1001-DEV&pdf=SPINAsmUserManual.pdf)
:icon_cool:
+1! 8) 8) 8)
Thank you!
My pleasure, glad I could be of some service!! I have been getting ready to make the jump over to the digital/dsp realm and have read about the femtoverb....thats why this clicked when I read over it.
For anyone on the board who is familiar with the Alesis AL3201, this chip seems very similar in design and architecture. It is a reverb/delay/modulation/dynamics processor, and probably should not be thought of as a full-fledged DSP. Built-in LFOs, single cycle LOG and EXP conversion, etc.
Unlike the Alesis chips, it has ADC and DAC on board. Basically, all you need to build a circuit is this chip, the pots needed for the parameters, yer usual box/switch/etc, and a 32.768 KHz watch crystal for the clock. And an EEPROM, if you design your own algorithms. It is surface mount, but only 28 pins.
Sean Costello
Very interesting indeed!! :icon_mrgreen: :icon_mrgreen:
This looks like a perfect opportunity for me to get started with DSP.
Does anybody have an idea how much such a chip (and eventually the developers kit) will cost?
This brings me to something I'm curious about: Assembly vs. C++.
My C++ knowledge is very limited, but my knowledge of assembly is non-existent. As I understand it programs for this chip have to be written in assembly and there's no compiler available that will compile C++ code into the right format.
Is assembly normally to be preferred above C++? How hard is it to learn assembly?
About the cost: Contact the distributor on the page. It seems fairly reasonable - more than some of the DSP solutions, but probably cheaper when you add in the built-in ADC/DAC, delay memory, and controller DACs. The development kit is also reasonable.
The FV-1 can only run 128 instructions per cycle. C++ just would not compile to efficient code (unless you create inline functions for C++ that are simply macros that map to the assembly instructions). The assembly syntax for the FV-1 is compact and VERY powerful: you can code an allpass delay in 2 instructions!!!
One caveat: the FV-1 does not look like the type of chip you can program an unlimited variety of DSP algorithms on. It does not have the horsepower for FFTs, bandlimited distortions are probably out of the question, the coefficient quantization imposes limits on what you can do, etc. On the other hand, delay buffer management is taken care of for you, the built-in LFOs are very powerful, and the EXP and LOG units are a dream for those of us who have had to come up with C and assembly approximations of these functions (did you ever use SCALB in C++?).
Sean
I spoke with their distributor a couple days ago and from what I remember the price breaks are as follows:
1-99: $10 ea.
100-999: $8.50 ea.
1000-4999: $7.50 ea.
Please don't quote me on that pricing schedule.
Once you factor in the other parts required for a design based around the Alesis Semi/Wavefront Semi Digital Reverb Engine, the FV-1 becomes a very complete and less expensive solution. Other little DSPs require an additional microcontroller to provide the kind of flexability and controlability that the FV-1 provides without outside help.
The FV-1 is limited in scope of the algorithms that it can handle, however it is still VERY powerful and it should do what it does rather well.
On programming: Assembly is the only language that the chip actually speaks and for me that makes it much easier to relate to that an abstract C++ program. I've been programming in assembly for over 20 years but I still don't do C++ and don't have any desire to. I just can't relate to C++.
As Sean mentioned above, the built-in EXP & LOG instructions and the addition of sine LFOs are very welcome features! 8)
I personally like programming DSPs in C. However, you need a good compiler to do so ($$$$), and you may have to use a lot of "intrinsic" operations, which are basically compiler hints to tell it what assembly operations to use. For the FV-1, you would have so many specialized instructions you would need to use, that it makes sense just to dive in and learn the assembly.
i wonder how quickly programs could be ported from the Alesis AL3201 to the FV-1? My concern with the FV-1 is the opposite idea: that an algorithm I create could easily be copied and ported over to the AL3201, or the Coolaudio V1000 if you want to get more precise about my fears. The FV-1 does not have a method of running encrypted code, so it would be easy to disassemble any code written on the external EEPROM. This would not be a concern for people who are using the built-in programs, or the (excellent) example code available on the FV-1 website.
Sean Costello
have no fear, Sean: I`m just an "as-is"-user... :icon_wink:
(with analogue surrounding ideas...)
sorry for the confusion, but hey now, what is this? (http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=RA-FX3C)
(if link won`t work, go here (http://www.profusionplc.com/),
and search for part# " RA-FX3C " ).
"resolute audio" :icon_question:
just got this offer from the distributor, that contacted me after having filled in Spin`s
contact-form...
first look seems larger S/N ratio than the Spin`s...
[EDIT:]
OK - I`ve searched after having had a closer look at the pdf picture:
"Nemesis" (http://www.my-nemesis.com/tech.html)...
whaddaya guys think?
[Edit 2:] another one... (http://www.profusionplc.com/images/data%20sheets/ra-fx1v.pdf) (inferior ?...)
The aforementioned Cooladio V1000 can be found here:
http://www.coolaudio-semicon.com/files/public/V1000_DATASHEET.pdf
How does the Spin FV-1 compare to this and the products mentioned by Puretube?
It looks like those boards could easily be based on the AL3201B/V1000.
I`ll give it a closer look with a magnifying glass, once they arrived...
Quote from: Arno van der Heijden on October 27, 2006, 04:29:01 AM
How does the Spin FV-1 compare to this and the products mentioned by Puretube?
I have not worked with either the FV-1 or the Alesis chips. However, the FV-1 was designed by Keith Barr, founder of Alesis, and the architecture of the DSP cores of both chips seem rather similar. I am not sure if the Alesis chips use the floating point representation for the delay lines.
Some of the differences between the FV-1 and the Alesis chip, from my admittedly inexpert position:
- FV-1 has built-in stereo ADC and DAC, while the Alesis requires external ADC/DAC
- Alesis requires high frequency crystal (in MHz), while FV-1 only requires a 32.768 KHz crystal, which should help FV-1 designs in RF testing
- FV-1 has really nice example algorithms, while Alesis has crappy example reverb code (you probably could port the FV-1 examples to Alesis, but that might violate terms of code licence)
- FV-1 seems like the assembly code is more concise. On the Alesis, you need to spend some cycles refreshing memory locations, and I haven't seen this in the FV-1 code.
Sean Costello
Quote
WWW
Re: Spin semiconductor fv-1
« Reply #10 on: October 27, 2006, 02:07:58 AM »
sorry for the confusion, but hey now, what is this?
(if link won`t work, go here,
and search for part# " RA-FX3C " ).
"resolute audio" icon_question
just got this offer from the distributor, that contacted me after having filled in Spin`s
contact-form...
first look seems larger S/N ratio than the Spin`s...
[EDIT:]
OK - I`ve searched after having had a closer look at the pdf picture:
"Nemesis"...
whaddaya guys think?
[Edit 2:] another one... (inferior ?...)
I'm happy we already have a wider choice for such chips/products without the hassle of PCB making and SMD soldering. Now after the reverb "problem" is solved I think these are /at least for what I need/ still "semi-solutions". I would like to see for example a chip/board which will allow for at least a chorus-delay-reverb FX chain with the option of individual /per effect/ parameters /all of them/ control and presets memorizing.
FV-1 comes close to that but still the parameters control is not flexible enough.
I have some chips out of the first batch made, and one of the developers kits/board. Seems like it cost $130, if I remember right.
It is not easy to port from the Alesis to this chip... in fact, it is not easy to understand how this chip works. I can program in several different assembly languages and the instructions for the FV1 are just not intuitive... definitely NOT recommended for the beginner. Its instructions are DSP specific and there's not much in the way of basic register instructions.... however, even though this makes it difficult, it also makes the chip quite powerful.
Because many basic instructions are missing, some types of DSP manipulations will be difficult or maybe impossible... the chip is really optimized for reverb/echo/chorus.
You'll need a programmer to load the ram if you intend to write your own code...
regards, Jack
The FV-1 is really more of a MAC (Multiply ACcumulate) unit with an instruction sequencer rather than a full featured DSP or microcontroller. It does what it does very well, but it's made for a specific purpose.
It seems a little funny, but the first way to make presets that comes to me would be to use a trio of e-pots with a microcontroller driving them. Analog->digital->analog->digital. :D
over here, the DEV-board is more like the "3" as first digit... :icon_eek:, and that`s in €...
Quote from: puretube on October 31, 2006, 12:41:41 PM
over here, the DEV-board is more like the "3" as first digit... :icon_eek:, and that`s in €...
As in €330? If so, that's steep! Do you want me to order you one and mail it to you?
-Jack
err, thank You for that kind offer, Jack; :icon_cool:
but I`m not intending to go into the depth of programming
this thing...
(but I had me sent the quotes from the euro-distributor,
who btw doesn`t have the "Spin" on his website, yet...).
Hi Jack,
Have you tried using it to develop envelope signals to control analog functions or filters (using the DSP digital filter capabilities or off the chip in analog using a DAC as a CV output)?
I'm still reading through the instruction set (assembler manual) and haven't got a feel for the capabilities of the chip yet beyond delay, reverb, and chorus\flange effects. Perhaps reading it all and looking through the code examples from the presets will make things clearer to me, and I just need more time with it. I'm trying to decide if I want to go for the development kit.
I've never programmed DSPs, but I have done assembler on plain vanilla uPs, and I'm trying to figure out if I can learn to program the thing in a reasonable amount of time. Barr writes in "his corner" that it is supposed to be fairly easy to program even for analog\non-digital types. Do you think the FV-1 seems harder to you because the instruction set is just so different from the general purpose DSP (so that someone like yourself who is used to the general purpose DSP instruction set has to stop and rethink how to do the same things on the FV-1 in a totally different way determined by the limited instruction set, i.e., do it Keith's way), or do you think the FV-1 instruction set is inherently flawed\awkward\too limited for anything except delay, reverb, and chorus\flange effects? I'm debating getting a development kit, but I don't want to blow $130 bucks to find out I can't really do what I want on it...
I'd like to hear more about your experience with it if you have time to share your thoughts about it.
Thanks
What is the current situation - how/where can one get any?
reduce the link in the 1st post to the basic URL,
and then browse the page thoroughly...
The FV-1 is fresh out of the gate and I don't know if all the final testing has been done yet. They should be available soon for $10 each in quantity 1-99 from OCT Distribution, Spin's U.S. distributor.
Maybe we can get Small Bear to pick this chip up? (are you listening Steve?)
I have a pair of them and THIS IS A REALLY EXCITING CHIP! 8) I also got a nice e-mail today from the FV-1's designer, Keith Barr (who was also the founder of Alesis and MXR). He even came through here (diystompboxes.com) today. 8)
I've got four FV-1 circuits on paper so far, including one that will be posted here for the DIY crowd under the name Lotus. It's an eight effect, four chip design including the voltage regulator :icon_biggrin:. As this does not require the builder to program a microcontroller, this circuit should be accessable to a pretty wide audience.
QuoteIt's an eight effect, four chip design
Do you mean 4 chips one after another? Something like chorus-delay-reverb chain or something?
i guess:
1.: power regulator
2.: input "conditioner" (buffer & splitter)
3.: FV-1 ("jack-of-all-trades)
4.: output "summer" (mixer)
:icon_wink:
:icon_question:
Very close :icon_biggrin:. The four chips are...
1. Power regulator to provide the logic with 3.3V (URL (http://"http://focus.ti.com/docs/prod/folders/print/ua78m33.html"))
2. Input "conditioner" (buffer & splitter) & output mixer (TL072)
3. FV-1 (jack-of-all-trades)
4. (optional) E2PROM for adding/changing algorithms (24LC32)
To this list, add a crystal and a handfull of resistors and caps, and you have a complete DSP effects unit with 1 second of delay memory.
I think most of the fun around here will be from changing the contents of the E2PROM. This gets us into the arena of I.P. protection as the real "work" becomes a series of easily accessible bytes in a generic memory chip. To head off any issues, all the code for the Lotus will be OPEN SOURCE. :icon_biggrin:
There is an extention to the Lotus design that adds a little microcontroller, a USB bridge chip, and a pair of optoisolators for programming while remaining free from any possible ground loops. The microcontroller serves as a translator to move serial data embedded in USB packets into I2C packets for writing into the E2PROM.
If you don't want to program effects but you want to change the operation of the device, all it takes is replacing the 24LC32 with a new chip which has been pre-programmed with different effects code.
Now, anybody want to guess what the six controls on the top of the box will be? ;)
hehe: just layouting an SMD PCB, with one conventional thru-hole part: a DIP8...
:icon_smile:
Quote from: puretube on November 03, 2006, 01:47:44 PM
hehe: just layouting an SMD PCB, with one conventional thru-hole part: a DIP8...
(http://img.photobucket.com/albums/v280/Snowberg/diy/bootsy.gif)
Okay, Peter, I'll give your control question a shot.
Controls 1, 2, and 3 are the 50k pots used as input controls
Control 4 is a blend knob for mixing the dry and wet signal
Control 5 is a program selector switch to switch between the 8 stored effects on the EEPROM (but not the internal effects, since it sounds like you're not using those).
Control 6 is a...gain knob? If not, it'll be a knob labeled "Good" that does just that.
The FV-1 does look like an interesting chip. After spending a lot time with the AL3201B, I think I'm ready to try something new.
Ordered my dev kit this afternoon. Stay tuned...
Matt Farrow
Quote from: puretube on October 27, 2006, 11:59:41 AM
I`ll give it a closer look with a magnifying glass, once they arrived...
so the mailman just rang the bell:
AL3201 & CS4271... (http://www.profusionplc.com/products/RA-FX1V.html) driven by a 8.192 quartz
plus: 2115 & a tiny ball-grid-array chippy I can`t decipher... (eprom?/µP?).
(btw: there`s a tiny name printed on the PCB beneath the word "NemFX":
"Marshall"
Just got the FV-1 eval board. Actually, I got it about 5 hours ago, and I've been playing with it all evening. So far I've "massaged" the delay example to suit my purposes and it seems to be going well. I'm definitely not used to assembler - only 1 variable! Well, not really, but the whole wrax, rdax thing is a bit new to me.
Anyway, sound quality is excellent, though the eval board is mostly set up to be used through a mixer. I stuck a simple opamp buffer / mixer on the little dev area on the eval board, and it's working fine for me so far. I'll keep everyone posted as I mangle this thing up some more.
Matt Farrow
Quote from: Peter Snowberg on November 02, 2006, 02:15:20 AM
The FV-1 is fresh out of the gate and I don't know if all the final testing has been done yet. They should be available soon for $10 each in quantity 1-99 from OCT Distribution, Spin's U.S. distributor.
Maybe we can get Small Bear to pick this chip up? (are you listening Steve?)
I will contact them as soon as I can get out from under stuff backed up from the trip.
BTW, the guy from OCT quoted me $8.50 for these chips in 100-1000s qty. If you just want to use the ROM programs in mono, you can build it with 1x dual opamp, the FV-1, and a 3.3V regulator. The ROM programs ARE pretty good, as you'd expect from Keith Barr. There's some flutter in the pitch-shift algorithm, but the reverbs are really nice, and the flange and chorus are pretty decent. There's some really smart code in the chorus program that scales the width of the chorus as the rate changes. Lots of good info there.
I've got the example delay program outputting the straight signal as well as using one of the pots to control the delay signal, and it looks like you can easily run this thing in stereo with just a dual op-amp to buffer the input. The output is beefy enough to be used as-is. However, this loses you one of the onboard pots since you have to use it as a mixer. But it does mean that you can build the thing all in software, which is nice.
I'm going to be messing around with some single-supply, low power opamps, so I can run the whole board from 3.3V. So far the LMV324 quad looks real good, in a 14-pin SOIC. I've got LM340-3.3's in SMD, as well as 33khz crystals. The EEPROM is going to be DIP so I can program the thing in the eval board, but for what I want to do with it right now I can basically use the layout on the eval board, just slap a pair of buffers on there for stereo inputs.
Any of you DSP-heads out there have any idea about reverse delay using this thing? I can write to the delay RAM, and then use a pot to control the pointer where the delay read happens. I'm wondering if there is any way to read the samples out of the delay in reverse order...
Right now, I'm working on a through-zero flange by delaying the straight signal by 10mS, then running the flange delay from 2-20mS.
Matt Farrow
Dave:
You got it. :icon_biggrin:
Control 6 is output volume.
Steve:
8) 8) 8) 8) 8) 8)
I hope you're having a great time in South America!
Matt:
Very cool! 8) I can't wait to hear your results!
Quote from: PharaohAmps on November 12, 2006, 10:55:51 AM
Right now, I'm working on a through-zero flange by delaying the straight signal by 10mS, then running the flange delay from 2-20mS.
Matt Farrow
Hi Matt,
You may want to scale back the fixed delay a bit. Even though it probably rocks for post-production processing, 10msec seems to me to be rather unsuitable fixed delay for live performance. The one advantage it presents is that one can spend more time on "the other side of zero" before returning. On the other hand, that can also be achieved by creative use of sweep waveform. Scott Stites (diyfreque) is probably the person to talk to here about what works and doesn't work well in TZF.
We've had numerous discussions on the main forum about TZF, and with so few people in a position to study it parametrically, it is difficult to reach some consensus about what is the minimum amount of fixed delay needed to achieve the most desirable effects. Scott's site (forgot the name/URL, but I'm sure you'll be able to find it) has some nice illustrations of what we've come to call symmetrical and asymmetrical TZF.
Quote from: Mark Hammer on November 14, 2006, 09:25:15 AM
You may want to scale back the fixed delay a bit. Even though it probably rocks for post-production processing, 10msec seems to me to be rather unsuitable fixed delay for live performance. The one advantage it presents is that one can spend more time on "the other side of zero" before returning. On the other hand, that can also be achieved by creative use of sweep waveform. Scott Stites (diyfreque) is probably the person to talk to here about what works and doesn't work well in TZF.
I remember the discussion about his Dimension C clone, I'll have to dig that back up. Right now my test program is running with the fixed delay at 1310 samples, about 4 ms at 32.7khz clock rate. The 10ms delay was definitely too much, but the experiments I did at 320 samples (1 ms) didn't get me enough time at zero.
Also, what you've said about LFO shaping is certainly relevant. I'm now messing with the ramp LFO's to get an asymmetrical triangle wave so I can do more "swooping" about the zero point. Right now it sounds good but lacks the drama I was looking for.
Next up is "barberpole" flanging, which from what I've read needs to incorporate a small amount of pitch shift. Hard to do well in analog, but easy as pie with the FV-1.
Matt Farrow
anyone hearing (intermodulation) artefacts with the fading signal?
or is that just my sloppy (partly unshielded) input-wiring
picking up signals from 2 battleing
cheap switch-mode powersupplies
(one for the e-board, the other for the amp)?
Well, I get all kinds of horrible noise from mine when it's connected to my PC over USB. :( But when I run it from a linear power supply (xfrmr -> bridge -> 9v regulator) I get no noise at all. Well, a bit of hiss from my mixer but nothing terrible. My input connection is super-crappy too, I just pulled up the R in and out RCA jacks and routed them to a TL072 as buffer and mixer. Works okay but I've got to get some 3.3v opamps to put it together in the end.
Nothing weird on the fading signal for me, could it be that as the s/n ratio goes down you're hearing it more?
Matt Farrow
ouff - I remembered that I hadn`t heard it in the beginning of experimenting...
guess what?
in the meantime I had my (relatively new) soldering station switched on
to solder some mono/stereo-adapter...
must be µP controlled, and adding to the wave-chaos... :icon_rolleyes:
after a night`s sleep, the intermodulation is still there without the solder-station,
but the scope verified, that the guitar-signal is already dirtied up by the sm-powersupplies, before it goes into the Spin...
gotta clean up the sloppy wiring!
what the scope discovered, too:
the Spin`s "dry" output signal is being phase-shifted from ~0° at very low frequencies
up to several thousands of degrees at high audio-frequencies
compared to the "original" (=input) signal.
when sweeping a signal-generator from low to high,
the 2 traces on the scope look like those of a >24 stage phaseshifter...
(I noticed this, when trying to watch the modulation-depth of the tremolo-preset).
:icon_eek:
Out of interest, why would one want to do anything with DSP?
The advantage of making your own pedals is that they are analog and thus much better sound than cheap multifx digital units? If you want the advantages of DSP, why not just by a DSP multifx machine?
Not being provocative, I just want to know.
a.o.: coz of the nonavailability of some BBD chips,
and to do things, you can`t easily do analog/non-mechanical:
Delay - Reverb - Pitching
and:
http://www.diystompboxes.com/smfforum/index.php?topic=42359.0
http://www.diystompboxes.com/smfforum/index.php?topic=23055.0
Quote from: RaceDriver205 on November 15, 2006, 06:13:07 AM
Out of interest, why would one want to do anything with DSP?
The advantage of making your own pedals is that they are analog and thus much better sound than cheap multifx digital units? If you want the advantages of DSP, why not just by a DSP multifx machine?
Not being provocative, I just want to know.
Multifx units that attempt to accomplish too many concurrent tasks for the processing power they pack get a deservedly bad reputation. DSP-based effects that do not attempt to reach farther than their capabilities can do some pretty special things. More and more single-function DSP pedals are turning up in the market and earning kudos from players who find them more than satisfactory. I still think that distortion is generally accomplished more effectively n the analog domain, but apart from that many digital pedals do a magnificant job. I am the proud owner of most of the Line 6 Tone Core pedals and I enjoy playing them as much as my 100% analog ones.
Certainly one of the things that digital has done extremely well over the years is reverb. Good reverb CAN be done entirely in the analog mode, but is often limited by the space required (got a spare 500-gallon oil drum, buddy? or would you mind hoisting this 5ft x 5ft plate reverb into the minivan for the gig?) and is subject to mechanical noise intrusion and very restrictive control over reverb parameters. A simple, cheap circuit that gives some control over a pleasing complex reverb is a wonderful thing to have available at one's disposal.
As for relatively trivial things like flanging, chorus, and simple delay, I would agree with you that sometimes these tasks can be accomplished quite well (and occasionally even better) in the analog domain for very modest cost and time/effort. When you get them thrown in for essentially free along with an extremely cost-effective digital reverb, though, it is too appealing to resist.
The other area where DSP often outshines analog is in the area of modulation. The sorts of circuits that could provide the modulation options available in many DSP-based pedals would require cost-prohibitive or space-prohibitive ciruitry to accomplish in the analog domain. I suppose if you're John Frusciante, and can have a wall of patched Doepfer, Modcan, Catgirl, or MOTM modules sitting offstage, operated by a tech, then you can go the all-analog route, but most musicians are not in that league. The modulation capabilities I have in my Tone Core Liqui-Flange (just a bit bigger and chunkier than a typical DOD pedal) would take something the size of that largest E-H pedals to accomplish in analog (maybe bigger) and even then it would be a tight fit, likely to be noisy, and bloody expensive. Small digital circuits may not yield ALL the flexibility of 100% analog, but they will easily take you 80% of the way there at a fraction of the cost and with 98% of the audio fidelity (well, as much as ears ruined by neodymium headphones and full-tilt iPods can detect).
Of course, here we reach a different sort of "digital divide". You and I can likely build analog circuits, and even improvise within that context, but when it comes to digital stuff we are hampered by the required knowledge. Heck, I understand a bit about assembler code, but I couldn't burn an EPROM if my family's life depended on it. Many folks look back with fondness on the golden era of electronics hobbyist magazines when the projects did not require $400 scopes and wads of PIC knowledge to build things. I know how they feel. Many beginners here stay completely clear of this separate forum, like it's some sort of dark alleyway where danger lurks. Happily, things like the SPIN chip have gone the distance to make many of the benefits of digital available to "regular folks" like us.
This is your roving cyber-reporter David, coming to you from the digital "Dark Side". Now that I've been assimilated by the digital Borg, I have the barest inkling of the beginnings of understanding of this shadowy realm. I believe the esteemed Mr. Hammer is right. Analog is preferable whenever possible (which is why my lonely, unlamented GT-3 is gathering dust in my gigbag -- which couldn't make me happier!) -- however, to mangle a quote from R.G., there are some things that are a lot easier to do digitally -- some of those being MIDI controllers, stompbox routers, loopers...
... and now this. I can't wait to see how this "Spin"s out!
I think I've had too much coffee... :icon_rolleyes:
Quote from: Mark Hammer on November 15, 2006, 10:40:12 AM
Certainly one of the things that digital has done extremely well over the years is reverb. Good reverb CAN be done entirely in the analog mode, but is often limited by the space required (got a spare 500-gallon oil drum, buddy? or would you mind hoisting this 5ft x 5ft plate reverb into the minivan for the gig?) and is subject to mechanical noise intrusion and very restrictive control over reverb parameters. A simple, cheap circuit that gives some control over a pleasing complex reverb is a wonderful thing to have available at one's disposal.
+1 on reverb. The FV-1 comes with some very decent reverb programs in its ROM. If all you want is a nice reverb, you can get away with an FV-1, a 3.3V regulator, and a dual opamp. Seriously.
If you want to get jiggy with it, then you can pick up an inexpensive serial EEPROM programmer (about $20 on ebay) that will work on 24LC32's, and the free software from Spin Semiconductor will make .HEX files. You don't really NEED the dev board, but its nice and quick. The FV-1 will do certain things MUCH better or at least much more easily than any analog circuit - reverb and pitch-shifting are good examples. It's easy to program and has a veteran effects designer behind it (Keith Barr.) It's a great starting point for DSP newbies.
Right now I'm working on interfacing the program pins to a PIC, so that I can change the clock speed and mute / unmute the straight signal when I change programs. It's pretty easy to do, actually, but I'm a PIC newb too :( One more thing to learn!
Matt Farrow
yes, a BIG THANX to Keith Barr!!!
[next step he takes, probably will be the 9V µ-power version:
<1µA in standby/bypass mode,
2mA (running thru an LED...), when ON;
with built-in electronic standby-detector (aka "mill-tbp",
so that a normal 4PDT stompswitch can be used for true bypass] :icon_wink:
+10000 on the thanks to Keith Barr. I have been designing reverbs for about 8 years now, and the example code that is on the Spin Semi site is AMAZINGLY good. I had figured out most of these techniques a few years back (by...um...doing a LOT of tests on a Midiverb 4), but to see them in print, complete with delay numbers and a theoretical explanation, is an embarrassment of riches. The other people associated with the company are also very helpful and informative - there is a forum on the Spin Semi site that a few people from the DIYstompboxes forum have started to visit.
My FV-1 development board should arrive by Friday. I am pretty excited. I hope to design a few of my own reverb algos, as well as some cool modulation effects.
Sean
Has anyone tried looping or even a hold reverb yet?
Quote from: Jack on November 17, 2006, 07:10:41 PM
Has anyone tried looping or even a hold reverb yet?
Yes. The 2nd one.
In rev_pl_1.spn, change line 54 from
sof 0.6, 0.3
to
sof 0.7, 0.3
This allows for the gain in the allpass ring recirculation to go up to 1.0, which results in infinite reverb.
No preconditioning of the signal yet to remove transients, but I just got the compiler running about 1/2 hour ago, and just started poking around.
This is fun...
Sean Costello
Quote from: Jack on November 17, 2006, 07:10:41 PM
Has anyone tried looping or even a hold reverb yet?
As for looping, I've messed around with a delay program with a nearly infinite hold, but with only 1 second of delay time (have to change the crystal that comes on the eval board to 32.768khz) there's not much joy to be had for the looper.
I'm working on a code snippet to use one of the POT inputs for a tap-tempo function. If you use an external mixer, you can get a really nice tap-tempo delay with feedback and delay time controls onboard, with no extra funny business. Total cost in parts is under $20, not including stomp switches and enclosure.
Any interest in a "generic" FV-1 board? Peter was talking about one with his Lotus board, but I've got to do some boards for my own production, and 100 boards isn't much more expensive than the 30 I need. If people want 'em I'm happy to sell.
Matt Farrow
Quote from: PharaohAmps on November 20, 2006, 07:38:23 AM
Any interest in a "generic" FV-1 board?
Why, yes! How thoughtful of you to ask! What feature set did you have in mind?
Quote from: David on November 20, 2006, 08:43:56 AM
Quote from: PharaohAmps on November 20, 2006, 07:38:23 AM
Any interest in a "generic" FV-1 board?
Why, yes! How thoughtful of you to ask! What feature set did you have in mind?
Well, the idea would be to implement everything that's on the datasheet: 3-bit program selector, 3 pot pins (these are CV, not audio, and you can use any pot you want,) and stereo in / out. One easy option is to use one of the signal inputs as a control input, and also to do the signal mixing in hardware to free up software controls. It's up in the air right now but I'll keep everyone posted.
Matt Farrow
Will the generic board have a place for an EEPROM?
I'm interested...
Thanks,
Sean Costello
That sounds pretty similar to what I have in mind. Keeping the mix control in hardware allows for the dry signal to be totally analog which is desirable for lots of people and it keeps the mix control from using up one of the three parameter controls. Since so much of the overall design is based around the FV-1 capabilities, if we all try to keep our boards similar, we'll end up with E2PROMs that can plug in anywhere. ;)
Peter, I'm thinking it might be better if we come up with something together, rather than trying to develop on our own. PM me if you're interested.
Matt Farrow
I vote for the MIX control in hardware IF it works.
Someone with a demo board needs to check on the effect of the reported frequency-dependent phase shift before designing a PCB with a hardware mix pot.
I'd buy a bunch of the PCBs if they had a space for the external EEPROM and a internal\external switch line.
Even if the FV-1 adds frequency-dependent phase shift, the MIX control would be useful. For flanger and phaser effects (where the phase of the mix is most critical), the programs could be developed such that the mixing of the modulated and straight signal happens within the FV-1 itself, and the MIX control should be advanced to fully wet signal in order to hear the effect. For chorus, having a nonlinear phase response of the delayed signal may not be such a bad thing. For reverb, any phase shift of the ADC/DAC is inconsequential, as reverb creates a highly nonlinear phase response, so having a little added by the ADC/DAC will not be noticable.
Sean Costello
agreed... :icon_wink:
Say, just noticed that the schematic for the FV-1 development board is now posted on Spin's site (in case anyone's interested).
Can anyone clue me in to what the big 56-pin chip connected to the USB is?
Cypress CY7C68013A
Fixed on the PDF now.
WELCOME to this (the) forum, Frank :icon_smile:
Welcome to the forum, Frank. :icon_cool:
I've been working on a leslie program for the FV-1. Looking to have someone critique it prior to posting it on the Spin site. If anyone is interested please email me for a copy of the program.
TL431 OK for creating 3.3V out of 9V from wallwart?
Quote from: TELEFUNKON on December 21, 2006, 05:10:27 PM
TL431 OK for creating 3.3V out of 9V from wallwart?
The TL431 is a voltage reference and not a regulator so I would use a device designed as a regulator instead. The difference between the devices isn't much, but regulators are generally a bit more robust than their reference cousins. The 431 would probably work fine, but I would suggest a low drop-out regulator like the LM1117 (Data Sheet (http://www.national.com/pf/LM/LM1117.html)) for the job.
tnx - will try to find them
the others I had found were all VLDO types
which can`t stand more than 8V input
or were of too large footprint.
then I thought about a TS78L05 (http://www.maplin.co.uk/Media/PDFs/Module%207933.pdf) followed by 2 or 3 diodes to drop more voltage,
but funnily enough, my supplier only has Rev.1 of the datasheet (compared to above Rev.B which I just found @ Maplin),
that does not show the pinout.
Just wondering if anyone knows of any distributors for this chip yet. I've tried contacting Spin Semi directly, but no response. Small Bear was going to try to get some in stock, but I haven't heard any updates on this.
look 4 posts back... (the sig in Frank`s reply #66 (http://www.oct-distribution.com/)... :icon_wink:)
(if you`re in Europe: mail these guys... (http://www.profusionplc.com/);
it may not be on their current website, but they were very quick with providing the goodies
with a little help of Frank!)
oufff, that took a while:
my usual supplier had the LM1117 (100/500/800mA) workalikes hidden behind some other nomenclature...
the other suppliers only offered large current 3.3V regs, that cost more than half of the Spin chip itself :icon_eek:
Quote from: jmasciswannabe on October 24, 2006, 12:57:41 PM
I don't know much of anyhting concerning this stuff, but ran across an add for it in the new products page in Music Inc magazine. It looked pretty rad especially with the analog potentiometer inputs. Searched for it on this board, but didn't find anything. Maybe a good chip for a project?...
THANX again, JMW, for pointing to this product! Much appreciated!!! :icon_smile:
Anyone come up with a standard PC board design for this, that they would like to share?
Alternately, anyone know of any good adaptors (sp?) to use the FV-1 in a perfboard design?
Thanks,
Sean Costello
reply #5 (http://www.diystompboxes.com/smfforum/index.php?topic=53826.0)
the middle one of the 3 layouts is the surf-adapter I made/use for it.
the problem: I don`t have a file for the layout, that is compatible with any of the known PCB-design software.
the low-most adapter in this pic (http://img.photobucket.com/albums/v437/latronax/SMD/SMD1810.jpg) is the spin.
http://www.futurlec.com/SMD_Adapters.shtml
Hi Puretube,
You're gonna make me have to investigate this chip. I've been studying the docs and it looks sooo cool !!!!
Thanks for sharing the adapter pics and layouts...
Glad this thread has kicked back up.
Greets to y'all
Quote from: puretube on November 15, 2006, 04:12:30 AM
the Spin`s "dry" output signal is being phase-shifted from ~0° at very low frequencies
up to several thousands of degrees at high audio-frequencies
compared to the "original" (=input) signal.
when sweeping a signal-generator from low to high,
the 2 traces on the scope look like those of a >24 stage phaseshifter...
This sounds like a straight delay - which would register as a low amount of phase shift at low freqs, and a high amount for high frequencies. A >24 stage phase shifter approximates a straight delay, assuming that all stages have the same poles.
My guess is that the delay is an artifact from the A/D and D/A convertors. Most convertors have some amount of delay inherent in them.
I'm all fired up on the FV-1 this week, so I will be digging up a lot of these old posts.
Sean Costello
Sean, did you see my layout yet, should help getting started with this chip as a pedal.
QuoteSean, did you see my layout yet, should help getting started with this chip as a pedal.
Good job on that one. If I remember this is the encoder that goes with it:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=GH3074-ND
http://www.alliedelec.com/Search/ProductDetail.asp?SKU=948-0431&SEARCH=&MPN=25LB22%2DH&DESC=25LB22%2DH&R=948%2D0431&sid=480E7C0046DFE17F
Quote from: Fp-www.Tonepad.com on April 22, 2008, 06:53:34 PM
Sean, did you see my layout yet, should help getting started with this chip as a pedal.
COOL! Are you going to have boards available for this project? I will try making one of these next week.
Is there any room on the board for output buffers? Or, do you think that a dual-ganged pot could mix input and output in the analog realm without too much loss?
Again, very exciting!
Sean
i'd definitely try the dual ganged pot mix.
I didn't want to add too much to it because there's always going to be a long list of features to add, i kept it really simple. Besides, there's two buffers on the board, you can use one of them for input an the other one for output. For mono use, the inputs should be tied together, which frees that extra buffer for output.
Hi guys! I'm a total newbie about digital stuff, but I saw this new project at Francisco's and thought this may be my first digital experience...
reading the datasheet I couldn't understand how you select the programs... it seems pins 16,17,18 are the ones... but on the proto-board it looks like there is a sort of pot to select the program... well, how does it work?!? ;)
thank you!
The device on the dev board for program selection is a rotary encoder, not a pot. It is a digital output device so it connects to the program selection pins to drive them high/low to select the program.
or you can use spst switches instead, even jumpers would work.
Look at the datasheet for program assignments.
External free programs found on Spin's website are much more interesting by the way.
The other way to select programs is to use an ordinary rotary encoder in combination with a small MCU /like PIC16F629 for example/.
Thank you guys! I think the three swithes array suits me better.. ::)
now it seems my problem is to find the chip :P
US: small bear (http://www.smallbearelec.com/Detail.bok?no=695)
EU: pro fusion (http://www.profusionplc.com/pro/gex/prodGen.html?prdtyp=reverb#)
up to you, to check the shipping costs... ( :icon_wink: )
It's quite funny... shipping costs within europe are double the price of the chip... :(
Get some more stuff, that way the chip/ship ratio will improve. :icon_wink: :P
I posted a short mod on the Spin forum (and in my blog) on how to double the amount of user-programmable memory for the FV-1.
Enjoy!
-Jack
I was thinking of replacing the pots with 8-bit DACs, driven by up/down binary counters, each program would have it's own set of counters (with CMOS I might even be able to save the counter info with battery backup) ... I've got a whole tube of 7-segment displays, I figure I could use these to monitor the outputs of the counters ...
BUT, I can't find a display driver that will do hex! The closest I've found are displays made by Avago with built-in decode/driver, but at $23.00(ish) per digit, not going to happen.
Anybody ever come across a solution other than Micro-controllers ?
Thanks,
Solutions off the top of my head:
DM9368 from Fairchild if you can find any
Programmable logic (i.e 22V10, cheap FPGA)
EEPROM (inputs to address lines, outputs to 7-segment)
Frank
OCT Distribution
Octfrank,
been unable to find the DM9368 (would have been the best solution, and surprising that it didn't catch on!)
the 22V10/CPLD is cheaper, but I then have to invest in a programmer, and some code generation.
EEPROM, more expensive, same footprint as 22v10, but way easier to implement, I might just pursue this avenue,
thanks for the ideas!
Does anyone know of a commercially available box using the FV-1 chip? I want to buy one for experimentation purposes.
Thanks, Jack
Quote from: amz-fx on September 16, 2008, 01:21:00 PM
Does anyone know of a commercially available box using the FV-1 chip? I want to buy one for experimentation purposes.
Thanks, Jack
I think the EHX Holy Stain uses one.
Quote from: tiges_ tendres on September 16, 2008, 01:44:21 PM
I think the EHX Holy Stain uses one.
Thanks. Anyone here have one that can confirm that?
regards, Jack
Hi all,
I've got two fv-1's but I just can't get them to work! Power supply is ok, everything is connected as it's supposed to be but no sound coming out of it....any ideas? Are these devices ultra sensitive to static and/or heat during soldering?
Any help will very much be appreciated...
Edwin
Edwin,
Email or post on the Spin website forum a full description and pdfs of the schematic and board layout.